Magnetic, electrical, and optical properties of Ca{sub 1-x}Ce{sub x}MnO{sub 3} (x {<=} 0.12) single crystals
- Russian Academy of Sciences, Institute of Metal Physics, Ural Division (Russian Federation)
- Moscow Power Engineering Institute (Technical University) (Russian Federation)
The magnetic, electrical, and optical properties of Ca{sub 1-x}Ce{sub x}MnO{sub 3} (x{<=}0.12) manganite single crystals are investigated with the aim of revealing the specific features of the multiphase electronic and magnetic state as a function of the cerium concentration and the atmosphere used for growing single crystals. It is found that the concentration dependence of the low-temperature magnetization M(x) of the single crystals is shifted toward the high-concentration range as compared to the corresponding dependence of the polycrystals, which is explained by the predominant cation deficiency. The electrical resistivity and the reflection spectra of the single crystals in the infrared spectral range indicate that charge carriers exhibit a band nature at temperatures close to room temperature. The temperature dependence of the electrical resistivity of the single crystal with x = 0.08, which has the maximum magnetization in the studied series of Ca{sub 1-x}Ce{sub x}MnO{sub 3} compounds, unlike polycrystals, exhibits a metallic behavior over the entire temperature range. The G-type antiferromagnetic phase with the Neel and Curie temperatures T{sub N}(G) = T{sub C} = 100 K is characterized by maxima of the electrical resistivity {rho} and the magnetoresistance {delta}{rho}/{rho} = vertical bar ({rho}{sub 0} - {rho}{sub H})/{rho}{sub 0} vertical bar = 38% in the magnetic field H = 90 kOe. The magnetoresistance {delta}{rho}/{rho} of the single crystals at cerium concentrations x = 0.10 and 0.12 with variations in temperature exhibit three specific features: near the temperature of charge ordering T{sub co}, near the temperature of the magnetic phase transition to the C-type antiferromagnetic phase T{sub N}(C), and near the temperature of the phase transition to the magnetic charge-ordered phase T{sub N}(MCO). An anomalous temperature dependence of the magnetization is revealed for a single crystal with x = 0.10 grown in oxygen at a pressure of 5 atm, which is explained by the presence of regions with hole conductivity due to cation deficiency. The inhomogeneous electronic and magnetic state is associated with the interrelation of the charge, orbital, and spin orderings.
- OSTI ID:
- 21246966
- Journal Information:
- Journal of Experimental and Theoretical Physics, Vol. 108, Issue 1; Other Information: DOI: 10.1134/S1063776109010129; Copyright (c) 2009 Pleiades Publishing, Ltd; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-7761
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ANTIFERROMAGNETISM
ATMOSPHERES
CALCIUM COMPOUNDS
CATIONS
CERIUM COMPOUNDS
CHARGE CARRIERS
CURIE POINT
MAGNETIC FIELDS
MAGNETIZATION
MAGNETORESISTANCE
MANGANATES
MONOCRYSTALS
OPTICAL PROPERTIES
OXYGEN
PHASE TRANSFORMATIONS
POLYCRYSTALS
REFLECTION
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K